Abstract: In a method of subsequent treatment of sulfur gas from waste pyrolysis, the sulfur gas is cooled after hot dust removal in many stages to an end temperature between 0.degree. and 5.degree. C., wherein the components [condensate] separated from the gas are subdivided into a heavy tar, an oil and a water phase. The obtained heavy tar is supplied back to the pyrolysis reactor, whereas the oil phase is again used partially or completely for gas treatment, and the separated water is discharged from the process. The end product of the method is a stable gas which can be used for heating.